1. Field of the Invention
The present invention relates to an automatic document feeder and an image reading apparatus using the same. More particularly, the present invention relates to an automatic document feeder that has an enhanced fixing structure of a friction pad so that a jam may be easily removed, and an image reading apparatus using the same.
2. Description of the Related Art
A multifunctional device having a copying function, such as a copier and a facsimile, employs an automatic document feeder (ADF). Therefore, documents can automatically be fed one sheet at a time and be copied in series without requiring opening and closing of a cover of the copying area when a number of documents are copied so that the time for copying can be significantly reduced.
The automatic document feeder generally has a structure in which an upper cover is opened to remove a document when a jam occurs during the feeding of the document.
Japanese Publication No. 10-017176, the entire disclosure of which is hereby incorporated by reference, discloses an example of the automatic document feeder.
FIG. 1 is a view of an automatic document feeder disclosed in JP 10-017176.
The JP 10-017176 discloses a document conveying part having a roller housing 147a in which drive rollers 143c′, 143d′ and 143e′ are disposed and that is rotatable upward around an axis 145a. A driven roller 143d″ is disposed in an upper stream guide 145. A driven roller 143e″ is disposed in a downstream guide 146. A driven roller 143c″ is disposed in a cover 148 and is rotatable around an axis 145a and has a second rotation region on the upper side.
When the cover 148 is rotated in the first rotation region, only the cover 148 is rotated in the second rotation region, the lock pin 148f of the cover 148 is locked in the insertion hole (not shown) of a side plate, and the roller housing 147a is rotated upward together with the cover 148.
Japanese Publication No. 2002-265090 discloses another example of the automatic document feeder.
FIG. 2 is a view of a conventional automatic document feeder disclosed in JP 2002-265090, the entire disclosure of which is hereby incorporated by reference.
The JP 2002-265090 discloses an automatic document conveyance device capable of removing jammed paper according to the following process. After opening a main body cover 23 and releasing pressurization of a paper feeding belt 11, a holding member 22 is moved to a release position to press a support member 26 by the holding member 22. The support member 26 is moved in the opposite direction to the direction of pressurization against the energizing force of a coil spring 27.
FIG. 3 is a cross-sectional view of a part of an image reading apparatus having a conventional automatic document feeder.
Referring to FIG. 3, the image reading apparatus includes a document feeding part 110 for automatically feeding a document and an image reading part 130 for reading an image of the fed document.
The document 113 supplied from the document supply tray 111 passes a separation roller 115 to separate into an individual sheet. A friction pad 117 is formed adjacently to an opposed surface of the separation roller 115 to provide a frictional force when the document 113 is separated. The document 113 separated into individual sheets by the separation roller 115 is conveyed via a conveying roller 114 to an image scan unit 131 formed at the image reading part 130. After being conveyed to the image reading unit 131, the document 113 has one side read and is then discharged via a discharge roller 119 so that the image reading process is completed.
The friction pad 117 is supported by a pad holder 121 that is elastically supported by an elastic member 123 toward the separation roller 115. One end of the pad holder 121 is connected with a bottom surface of the document support tray 11.
The reference numeral 125 denotes a cover member capable of opening and closing up and down.
However, in the conventional image reading apparatus, the friction pad 117 is in contact with the separation roller 115 by the elastic member 123. Therefore, when a jam occurs and the document 113 is pulled out in a direction indicated by arrow A, the document 113 may be not removed or torn due to both of the rotation direction of the separation roller 115 and the mutual pressurizing of the separation roller 115 and the friction pad 117.
Accordingly, a need exists for an automatic document feeder having an improved friction pad to facilitate clearing of a paper jam.